I haven't as much experience as some of you guys that I've been reading about here, but back in the early 70's I worked on a couple of mainframes, a Burroughs B2700, and an ICL1902T both as operator and operator/asst programmer. Languages used were COBOL and Fortran/Fortran IV along with BASIC.
I'm pleased to see a forum that is dedicated to Mainframes, I have many fond memories of my time working with them. (though some of the memories are a little rusty these days lol)
Nice to meet everyone here and my best wishes for the future success of this forum.